The present invention relates to a case for holding a number of charts in a ready reference position. In a typical prolonged trip, the boat operator will have to refer to a number of charts in sequence. It is exceedingly difficult to handle the charts one by one and to store them in a moisture proof condition. It is important that they be jacketed against exposure to water and other liquids during the trip as well as during their use. The transparent holder for each chart makes it possible to mark the route with a grease pen right on the holder.
It will be understood that the present invention is suitable for use in aircraft, military vehicles or even for construction blueprints.
A number of prior art solutions to the problem are known. For example in U.S. Pat. No. D. 153,332 issued on Apr. 12, 1949 to R. H. Armstrong for "Chart Housing", there is shown a rolled up or scroll type arrangement for holding charts. This system is not appropriate where more than one chart has to be referred to. Nor does it provide the necessary waterproof storage for the charts.
A further approach is shown in U.S. Pat. No. 1,471,481 issued on Oct. 23, 1923 to P. P. Gobberdiel, for "Tourist's Guide". That patent shows a plurality of rigid frames for holding individual travel sheets or similar data. The individual frames however are not readily removable for reference nor for placement one relative to the other in a sequential arrangement.
U.S. Pat. No. 3,807,071 issued on Apr. 30, 1974 to J. T. Candor for "Frame Construction For a Plural Page Document". This patent shows a carrier for a number of documents which are pivotally held at their upper ends to provide fanning out for reference to the individual sheets. It does not however show a system in which the individual sheets are readily removable for reference and for sequential line-up, one relative to the other.